Reporting results of its biennial review of industry’s enforcement of its voluntary ratings systems for theaters as well as DVDs and videogames, the FTC generally gave the entertainment industry good marks.

The FTC said its secret shoppers—unaccompanied 13 to 16-year-olds—went to 250 theaters, and ran into much more difficulty buying tickets to R-rated movies.

“Ratings enforcement at the movie box office is at its highest level since the FTC began its mystery shopper program in 2000,” said the report. “Less than one-quarter of underage shoppers were able to buy a ticket to an R-rated movie, down from one-third in 2010."

The FTC said enforcement was especially high at four of the seven major theater chains.

AMC Entertainment turned away 95 percent of the teens trying to buy tickets to R-rated movies, and Regal Entertainment and Marcus Theaters also demonstrated high levels of enforcement.

Rick Quaresima, the FTC’s assistant director of advertising practices, told TheWrap the latest study buttressed a trend the FTC has seen toward greater enforcement of the voluntary ratings.

The FTC began doing the reports at the request of Congress, amidst complaints that the voluntary system used for the entertainment industry’s ratings weren’t being enforced by theaters and stores.

Besides going to movie box offices, the FTC sent the “secret shoppers” out to stores to try to buy R-rated and unrated DVDs, music CDs with “Parental Advisory” labels, and videogames with M-rated labels. Shoppers attemped to make a buy in each category 250 times.

The latest report said 30 percent of shoppers were able to purchase R-rated movie DVDs compared to 38 percent in 2010, and 30 percent were able to buy unrated DVDs, down from 47 percent in 2010. The FTC said Blockbuster, Best Buy, Walmart, and Kmart denied more than three quarters of purchase attempts.

On music CDs, the FTC said retailers are increasingly turning away children attempting to purchase music CDs bearing the Parental Advisory Label. Less than half of underage shoppers (47 percent) were able to purchase CDs with this label, down from 64 percent in 2010 and 72 percent in 2009.

In videogames, where compliance was already highest, the FTC reported little change.

It said 13 percent of underage teenage shoppers were able to buy M-rated video games, unchanged from the last report.

National Association of Theater Owners President John Fithian said Monday in a statement that his group is “proud of the significant improvement in ratings enforcement” in the nation’s theaters.

“This report and its results continue to reinforce the importance and effectiveness of the voluntary ratings system,” Fithian said. “As the Supreme Court noted in its decision in Brown v. EMA, retailers’ voluntary enforcement of the ratings provide an effective alternative to state regulation. We will continue to do our part in enforcing the voluntary ratings system that allows creators to create and parents to make informed decisions about their children’s entertainment.”